This book tackles an essential question for human survival in the 21st century: will we be able to transform our lives, businesses, buildings, settlements and the transport networks connecting them from unsustainable, oil-based and greenhouse gas emitting into sustainable, fossil fuel-free, zero-carbon metabolisms? This book and its two dozen contributors show that this path is necessary, practical and affordable. These essays provide a roadmap for delivering fundamental change in the way we bring new energy technologies to market. The book emphasizes the key role that renewables can play in our urban energy picture.